Diametral fan



Dec. 2, 1969 A. cs. KOROVKIN 3,481,530

DIAMETRAL FAN Filed Jan. 17, 1968 3,481,530 DIAMETRAL FAN AnatolyGrigorievich Korovkin, Ulitsa Dovatora 11, korpus 2, kv. 38, Moscow,USSR. Filed Jan. 17, 1968, Ser. No. 698,555 Int. Cl. F04d 17/08, 29/52;F0111 1/30 US. Cl. 230125 3 Claims ABSTRACT OF THE DISCLOSURE Adiametral fan having a rotatable impeller with curved vanes within whichis mounted a guide apparatus including alternating long and short vanesrespectively having outer edges in close proximity with the vanes of theimpellet, whereas the inner edges of the outer vanes are also in closeproximity with the vanes of the impeller, while the other vanes of theguide apparatus have inner edges remote from the vanes of the impeller.The end vanes of the guide apparatus define an entry at the inlet asmeasured along the arc of the impeller which substantially exceeds theoutlet as measured from the outer edges along the arc of the impeller.The curvature of the vanes of the impeller and their spacing and thecurvature of the vanes of the guide apparatus is such as to providerelatively high pressures at comparatively low circumferentialvelocities of the impeller.

The present invention relates to installations adapted to transfergases, and more particularly, to diametral fans.

Diametral fans known heretofore comprise an impeller whose vanes aremade concave in the direction of rotation of the impeller. The axis ofrotation of the impeller isperpendicular to the direction of flow of thegas being transferred. The impeller accommodates an impeller guide vaneassembly or guide apparatus which is capable of changing the directionof the gas flow emerging from that portion of the impeller which is inthe vicinity of the delivery pipe of the fan (cf., e.g., FRG PatentsNos. 807,978 and 1,074,816).

The values of the maximum coefficient H of the total pressure (F=H/pu2)in these fans do not exceed H =2 to 2.2, the coefiicients of the fancapacity Q being equal to 1.4 or 1.5, where H is the total pressure ofthe fan in kg./sq. m., Q is the fan capacity in cu. m./sec., p is thedensity of gas in kg./sec. /m. b is the width of the impeller in m., Dis the impeller diameter as measured at the vane tips in m., and w isthe circumferential velocity of the impeller vane tips in m./sec. (cf.,e.g., .FRG journal Heizung, Liiftung, Haustechnik, No. 12, 1957, p.324). However, in case the diametral fans of said type are employed totransfer gas at a relatively high pressure, their overalldimensions andthe circumferential velocity of the impeller should be considerablyincreased.

It is, therefore, the principal object of the present invention toprovide a diametral fan which will feature relatively small overalldimensions and weight and be capable of ensuring relatively highpressures at comparatively low circumferential velocities of theimpeller.

According to the present invention said object is attained due to thefact that the ratio between the deflection f of the center line of theprofile of the curved impeller vane and the vane chord lies within 1:3.5to 124.5, the angle of inclination p of the chord B relative to theimpell r radius r drawn to the vane tip equals 1520 deg., the relationbetween the chord B and the vane spacing t equals 1.5-2.0, the vanes ofthe impeller guide vane assembly United States Patent ice or guideapparatus are arranged so that the angle '7 between the tangent AA tothe exit edge of the guide vane and the straight line directed oppositeto the vector of the circumferential velocity of the impeller does notexceed deg., and the ratio m/n between the lengths of the arcs m, n, atthe inlet and exit edges of said vanes equals 1.5-1.6.

The test model of a diametral fan made in accordance with the presentinvention has the maximum pressure ratio I I equal to 3, and a capacityfactor Q equalling 1.6.

Given hereinbelow is a detailed description of an exemplary embodimentof the present invention with due reference to the accompanyingdrawings, in which:

-FIG..1 is a longitudinal section through a diametral fan, according tothe invention (longitudinal section);

FIG. 2 shows a portion of the impeller and of the impeller guide vaneassembly or guide apparatus taken on an enlarged scale.

The diametral fan of the invention comprises" impeller 1 (FIG. 1)accommodated in housing 2. Suction and delivery pipes 3, 4 are arrangedperpendicular to the axis of rotation of the impeller 1. Mounted in thecentral portion of the impeller 1 are fixed curved vanes 5, 6, 7, 8 and9 of an impeller guide vane assembly or guide apparatus, a cascade ofcurved vanes 10 of the impeller 1 rotating with respect to said fixedvanes. Gas is admitted to the impeller 1 via the suction pipe 3 and fromvane channels of the impeller which pass near the pipe 3, said gasenters vane channels defined by the vanes 5, 6, 7, 8 and 9. Said vanesbeing curved in shape, the direction of the gas flow is changed and thegas is fed at a preset angle to the vanes 10 of the impeller 1 whichpass near by the delivery pipe 4.

The vanes 10 of the impeller .1 are made concave in the direction ofrotation and are arranged along the circumference of the impeller. Therelation between the deflection (FIG. 2) of the center line of theprofile of each vane 10 and the chord B of said profile is within 1:35to 1:45. The angle ,8 of inclination of the chord B relative to theradius r of the impeller 1 drawn to the tip of the vane 10 equals 15-20deg. The relation between the chord B of the vane and the spacing t ofthe vanes 10 equals 1.5 to 2.0.

The vanes 5 and 8 of the impeller guide vane assembly or guide apparatusare arranged so, that their inlet edges adjoin the exit edges of thevanes 10 of the impeller 1, in the region of the outlet of suction pipe3, with a small clearance, whereas the inlet edges of the vanes 7 and 8,are disposed at a relatively great distance from the exit edges of thevanes 10. The exit edges of vanes 5, 6, 7, 8 adjoin the inlet edges ofvane 10 near the inlet of the suction pipe 4. It is obvious that whenthe impeller is rotating, the exit edges of the vanes 10 arranged nearby the suction pipe 3 become the inlet edges as disposed near by thesuction pipe 4.

The inlet edges of the vanes 5, 8 are arranged along an are In (FIG. 1),and the exit edges of the vanes 5, 6, 7 and 8 are arranged along the aren. The ratio m/n is 1.5 to 1.6. Located between the vanes 5, 6, 7 and 8are the vanes of a smaller length, whose exit edges are disposed alongthe are n.

The angle '7 (FIG. 2) between the tangent AA at the exit edge of any ofthe vanes 5, 6, 7, 8, 9 and the straight line directed opposite to thevector of the rotational velocity of the impeller 1 (a line tangent tothe impeller periphery) does not exceed 90 deg.

What is claimed is:

1. A diametral fan comprising a rotatable impeller with curved vaneswhich are concave in the direction of rotation, each said curved vanehaving a deflection at the center which is in a ratio between 123.5 and1:45 with respect to its chord, the chord being inclined and forming anangle of inclination relative to a radius of the impeller of a valuebetween 15-20, said vanes being circumferentially spaced at a distancewhich is in the ratio between 1:1.5 and 122.0 relative to said chord; afixed guide apparatus within said impeller for guiding the flow acrossthe impeller and including alternating long and short vanes havingrespective inner and outer edges, said outer edges of the vanes beingcurved in the direction opposite to the direction of rotation of theimpeller, each having a tangent at the outer edge thereof which forms anangle with the straight line directed opposite the vector of thecircumferential velocity of the impeller which is less than 90, saidvanes of the guide apparatus forming at their inner edges an arcmeasured along the impeller which is in a ratio with the are formed bythe outer edges of the vanes of the guide apparatus as measured alongthe inner diameter of the impeller of between 1.5 and 1.6.

2. A fan as claimed in claim 1, wherein the outer edges of all of thevanes of the guide apparatus are in equal close proximity to the vanesof the impeller.

3. A fan as claimed in claim 2, wherein the end vanes of the guideapparatus are long vanes and have inner edges in close proximity to saidvanes of the impeller, the remaining vanes of the guide apparatus havinginner edges disposed within the impeller in substantial spaced relationfrom the vanes thereof.

References Cited UNITED STATES PATENTS 2,658,700 11/1953 Howe 230-1252,942,773 6/1960 Eck. 3,23 8,725 3/1966 Ludin.

HENRY F. RADUAZO, Primary Examiner US. Cl. X.R. 230-133

